| Month | Temp. (min) | Temp. (max) | Temp. (avg) | Precipitation |
| January | 10°F | 25°F | 17°F | 0.2" |
| February | 11°F | 28°F | 18°F | 0.3" |
| March | 25°F | 43°F | 33°F | 1.1" |
| April | 38°F | 59°F | 47°F | 2.2" |
| May | 50°F | 69°F | 58°F | 1.3" |
| June | 61°F | 82°F | 70°F | 1.9" |
| July | 64°F | 84°F | 74°F | 0.9" |
| August | 60°F | 80°F | 70°F | 8.9" |
| September | 55°F | 76°F | 64°F | 11.0" |
| October | 44°F | 62°F | 51°F | 9.0" |
| November | 27°F | 44°F | 34°F | 0.6" |
| December | 11°F | 24°F | 17°F | 1.0" |
| Index | Monticello | Minnesota | National |
| Air quality index | 32 | 35 | 42 |
| Pollution index | 2,322,880 | 1,854,519 | 2,726,193 |
| Measurement | Total |
| Days measured | 344 |
| Days with good air quality | 313 |
| Days with moderate air quality | 31 |
| Days w/ poor A.Q. for sensitive groups | 0 |
| Days with unhealthy air quality | 0 |
| Pollutant | Total |
| Arsenic | 0.040% |
| Benzene | 0.030% |
| Carbon Tetrachloride | 0.001% |
| Lead | 0.360% |
| Mercury | 0.290% |
| City | Population | Air Quality Index | National Avg. |
| Clear Lake, MN | 692 | 32 | 36.0% |
| Big Lake CDP, MN | 390 | 32 | 36.0% |
| Zimmerman, MN | 6,045 | 32 | 36.0% |
| Clearwater, MN | 1,690 | 32 | 36.0% |
| Big Lake, MN | 11,468 | 32 | 36.0% |
| Monticello, MN | 14,058 | 32 | 36.0% |
| City | Population | Air Quality Index | National Avg. |
| Grimes, IA | 14,059 | 39 | 22.0% |
| Beauharnois, QC | 14,056 | n/a | |
| Kailua CDP (Hawaii County), HI | 14,062 | 30 | 40.0% |
| Holly Springs, GA | 14,053 | 52 | 4.0% |
| Marietta, OH | 14,053 | 35 | 30.0% |
| Monticello, MN | 14,058 | 32 | 36.0% |